At this point, after a lot of research, I feel like I understand #2, "UMA" = "GSM over IP".

But what I am having problems with now is #3 - is there any way to get a discount on that "IP over GSM" traffic?

If I add #1 and #3 together, then I'm looking at $75 a month, and if I add on Hotspot, then I'm at $85 a month!!!

There are a few pages at T-Mobile which imply that there might be such a thing as "bundled Minutes & Mail plans". [New user - can't post links yet - sorry.] But I couldn't find any such "bundles" at the T-Mobile store, and when I called the T-Mobile customer service rep, she was just utterly clueless [in all honesty, the poor girl sounded like she was illiterate].

What I would like is some sort of a bundle which allows me to use "IP over GSM" data minutes [#3] as though they were regular GSM voice minutes [#1] - i.e. I want just one big pot of minutes that I can use for either data or voice.

But I'm not finding any such thing on the T-Mobile website.

[By the way, that's how UMA without Hotspot works: If you use UMA without Hotspot, then you get a big pot of minutes and you can use them as either old-fashioned "GSM" or as UMA = "GSM over IP" minutes.]

Finally, is #4 even theoretically possible? If I go into a Starbucks/Borders/Barnes&Noble/Public Library with 802.11b/g, then with a Blackberry 8900 can I get on the internet using raw TCP/IP packets over 802.11b/g, with no involvement by T-Mobile whatsover?

If #4 is a realistic possibility, then I could ditch #3 altogether [$34.99 X 12 = $419.88 per year] and just drive to where I can get good WiFi reception, and check my email for free.